The January greenhouse is a mellow place: A sheltered haven from the vagaries of the weather and a real godsend to the active gardener.
Established greenhouses in January will be harbouring all manner of overwintering plants and cuttings and a few seedlings too, protecting them from the vagaries of the weather outside. But as the days lengthen and the temperature warms, the greenhouse gardener can get growing in earnest.
Don’t get too excited, pace yourself for the best results.
If you have a heated propagator or a heated bench then you can start to sow some plants from seed that need a long season to perform to their full potential, plants like tomatoes where the most exciting varieties can be grown from seed really benefit from an early sowing, but you need to make sure that you have somewhere frost free and ideally a pretty constant 65F for the best results.
You can provide this with thermostatically controlled soil warming cables, but you do need to weigh up the costs involved. It’s only worth doing if you are growing varieties that you cant buy as seedlings or young plants later. Or if you have plenty of other plants to grow that demand the warmer climes.
Germinating the seed is only part of the process, you need to keep them hale and hearty until they are ready to pot up into their final growing bags or planters, or until you can harden them off for growing outdoors.
Remember that although there is a lot to be said for sowing early and getting an earlier crop you can cheat by buying seedlings that have been grown by someone else, this will save you heating costs early in the season and allow you to prick them out, pot them up and grow them on as the weather starts to warm.
There is usually a fair choice available, so unless you want to grow obscure or unusual varieties or you are a real tomato aficionado then this may be a better bet for you.
January is a month of getting ready for the season ahead, washing pots, buying all the accessories you might need such as modules, seed trays and labels, and washing clean all those that you used last season. Stock up on some fresh, this season seed compost and keep it in the greenhouse to acclimatise.
Buy a couple of small bags and replace when you’ve used them up so that you have a fresh supply of compost.
Spend time enjoying your seed catalogues and planning your greenhouse and garden year ahead. Make a list first and see whether you can afford everything on your list, growing from seed does save money but it is so easy to get carried away by the promise of rare and beautiful flowers and vegetables.
Try and keep your greenhouse frost-free at all times and then you expand the use of your greenhouse. Buy your seed potatoes and chit them in an open, light and frost-free place to give them a head start.
Bring pots of planted bulbs into the greenhouse for an earlier display then place them back outside when they are in flower. If they are established pots of bulbs, then top-dress them with fresh compost.
Keep a careful eye out for greenhouse pests such as slugs and snails and control using your preferred method. Watch out also for common plant diseases such as botrytis. On sunny days open the greenhouse vents and doors for an hour or two to ventilate and avoid overcrowding your plants. Sow winter lettuce and leafy salad leaf crops such as perennial rocket, lambs lettuce and sow seed onions into modules and leeks into trays or pots ready to plant out when large enough.
Arrange your greenhouse so that you have a chair in a corner to enjoy some early, protected sunshine, it’s a great retreat and a wonderful place to wile away a few hours.